diff --git a/docs/AllRectorsOverview.md b/docs/AllRectorsOverview.md
index a78d655b202..e5c4edeb285 100644
--- a/docs/AllRectorsOverview.md
+++ b/docs/AllRectorsOverview.md
@@ -3547,7 +3547,7 @@ services:
 
 - class: `Rector\Php\Rector\FuncCall\PregReplaceEModifierRector`
 
-The /e modifier is no longer supported, use preg_replace_callback instead 
+The /e modifier is no longer supported, use preg_replace_callback instead
 
 ```diff
  class SomeClass
diff --git a/docs/NodesOverview.md b/docs/NodesOverview.md
index d84b5e95620..e5a0a4b3b9d 100644
--- a/docs/NodesOverview.md
+++ b/docs/NodesOverview.md
@@ -917,7 +917,7 @@ if (true) {
 
 ```php
 ?>
-<strong>feel</strong><?php 
+<strong>feel</strong><?php
 ```
 <br>
 
diff --git a/packages/CodeQuality/src/Rector/FuncCall/StrlenZeroToIdenticalEmptyStringRector.php b/packages/CodeQuality/src/Rector/FuncCall/StrlenZeroToIdenticalEmptyStringRector.php
index 7a1dea13e28..53a26214ed5 100644
--- a/packages/CodeQuality/src/Rector/FuncCall/StrlenZeroToIdenticalEmptyStringRector.php
+++ b/packages/CodeQuality/src/Rector/FuncCall/StrlenZeroToIdenticalEmptyStringRector.php
@@ -64,9 +64,7 @@ CODE_SAMPLE
             }
 
             $variable = $node->left->args[0]->value;
-        }
-
-        if ($node->right instanceof FuncCall) {
+        } elseif ($node->right instanceof FuncCall) {
             if (! $this->isName($node->right, 'strlen')) {
                 return null;
             }
@@ -76,6 +74,8 @@ CODE_SAMPLE
             }
 
             $variable = $node->right->args[0]->value;
+        } else {
+            return null;
         }
 
         /** @var Expr $variable */
diff --git a/tests/PhpParser/Node/Value/ValueResolverTest.php b/tests/PhpParser/Node/Value/ValueResolverTest.php
index 7a191189b41..a16718451e7 100644
--- a/tests/PhpParser/Node/Value/ValueResolverTest.php
+++ b/tests/PhpParser/Node/Value/ValueResolverTest.php
@@ -2,7 +2,7 @@
 
 namespace Rector\Tests\PhpParser\Node\Value;
 
-use Generator;
+use Iterator;
 use PhpParser\BuilderFactory;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\BinaryOp\Plus;
@@ -28,17 +28,13 @@ final class ValueResolverTest extends AbstractKernelTestCase
     /**
      * @dataProvider dataProvider
      * @param mixed $expected
-     * @param Expr $expr
      */
     public function test($expected, Expr $expr): void
     {
         $this->assertSame($expected, $this->valueResolver->resolve($expr));
     }
 
-    /**
-     * @return Generator
-     */
-    public function dataProvider(): Generator
+    public function dataProvider(): Iterator
     {
         $builderFactory = new BuilderFactory();